plant evolution

I received the following (solicited) message from a student in a non-majors'
class.
"I was wondering if you could post some key sources that explain the
evolution of plants. I was just wondering where the scientists get their
information about plant evolution over hundreds of millions of years. Isn't
most of this information just speculation? I would greatly appreciate it if
you could provide some more insight on this. Thanks!"
(Iowa freshman: polite and cheerful.) I would guess that his mind is made
up, but I do want to be able to provide sources for him. Can anybody help
me? Web addresses would be especially useful.
My greatest victory in this department was a student who once wrote, "I
don't believe it happend this way, but for the first time I understand why
others do." Education happens!
--Gini Berg
Today three billion people will eat rice.
The genome is being sequenced.
Virginia Berg (bergv at uni.edu)
Biology Department 0421
University of Northern Iowa
Cedar Falls, IA 50614
(319) 273-2770 (phone), 273-2893 (fax)
http://www.uni.edu/berg
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